STC finding closure
Closing gaps in the ICA package for a STC
This work closes a STC finding where the Instructions for Continued Airworthiness leave part of the approved modification without a maintenance task, a limitation, or an airworthiness limitation. An engineer reads the ICA against the modification it is supposed to cover, finds the installed parts and functions that have no continued-airworthiness instruction, and maps each one to the task, interval, or limitation it needs. It runs while a modifier is under review and the ICA has been called incomplete. You receive a closure brief describing the coverage gaps and how they close, an evidence request list for the source data still needed, and a disposition package the reviewer can accept.
When this review is needed
- A reviewer has found installed equipment in the modification that the ICA never assigns a maintenance or inspection task.
- An airworthiness limitation implied by the design analysis is missing from the limitations section of the ICA.
- The ICA was drafted against an earlier configuration and a later change added parts it does not address.
- The modification affects an existing maintenance program task and the ICA does not say how the two interact.
The problem
An ICA reads as complete until someone walks it against the actual bill of materials and the design analysis behind the modification. Then the holes appear: a filter with no cleaning interval, a bonded joint with no inspection, a limitation that lives in the stress report but never made it into the limitations section. The people who wrote the ICA often did so before the configuration froze, and reconciling it to the final build takes an engineer who can read both the maintenance intent and the certification analysis.
What gets reviewed
- The installed configuration walked against the ICA to find parts and functions with no assigned task
- Airworthiness limitations from the design and stress analysis checked into the ICA limitations section
- Inspection, servicing, and replacement tasks confirmed present with intervals and access instructions
- Interaction between the modification and the existing maintenance program tasks stated explicitly
- Late configuration changes checked for the ICA content they should have triggered
- Each closed gap mapped to the source data that justifies the task or limitation
What gets validated
- Every part in the modification that requires maintenance has a corresponding task in the ICA with an interval
- Each airworthiness limitation traceable to the substantiation analysis appears in the ICA limitations section
- Servicing and inspection tasks name the access, tooling, and criteria needed to actually perform them
- Where the modification touches an existing program task, the ICA states the effect rather than leaving it implied
- The ICA structure and numbering follow the format the reviewing authority expects for the modification class
Evidence normally required
- The current ICA document for the modification
- The approved or proposed configuration bill of materials and installation drawings
- The design substantiation and stress analysis that generate any limitations
- The affected aircraft maintenance program tasks for interaction checks
- The reviewer's finding text describing what the ICA fails to cover
Common discrepancies
- Installed equipment with a defined service life that the ICA gives no replacement task
- An airworthiness limitation present in the stress analysis but absent from the ICA limitations section
- An inspection task written without the access instruction needed to reach the item
- A late-added component that the ICA, frozen against an earlier build, never mentions
What is at stake
An ICA with coverage gaps keeps the finding open and stalls the approval, because the reviewer cannot sign off instructions that leave part of the modification unmaintained. If it slips through, the operator inherits equipment with no defined upkeep, and a missing airworthiness limitation can become a fleet-wide correction once it is caught, long after the STC is in service.
Move from findings to resolution
Identify the missing data behind the finding.
How the work runs
Walk the configuration
Compare the installed bill of materials against the ICA to find parts and functions with no task.
Harvest the limitations
Pull every airworthiness limitation the design and stress analysis imply and check each into the ICA.
Map each gap to content
Assign the task, interval, or limitation that closes each gap and tie it to source data.
Package for review
Write the closure brief, list outstanding evidence, and map the completed ICA to the configuration.
What the buyer receives
Who uses the output
- Certification engineers responding to the reviewer's ICA finding
- Program managers clearing the ICA gate before the approval can advance
- Technical publications staff incorporating the mapped tasks and limitations into the ICA document
How the work fits into the transaction or program
ICA closure comes late in a STC, after the configuration is stable enough to know what will actually be installed and maintained. It depends on a settled configuration baseline and the completed design analysis, and its output becomes the continued-airworthiness content the operator relies on, so a gap here carries straight into service if it is not caught before approval.
Start with a single asset
Confirm each requirement maps to substantiating evidence.
Jurisdiction-specific considerations
FAA and EASA differ on how airworthiness limitations are formatted and where they live relative to the rest of the ICA, so the closed gaps are mapped into the structure the reviewing authority expects rather than a single format assumed to satisfy both.
Regulatory limits
This work identifies coverage gaps and maps each to the task or limitation it needs. It does not author the underlying design analysis, set intervals on an authority's behalf, approve the ICA, or determine that the modification is airworthy.
What this review does not cover
- Developing new substantiation analysis to justify a task that has none
- Setting or approving maintenance intervals as a regulatory act
- Any airworthiness determination on the modified aircraft
Specific to this review
- A missing airworthiness limitation is the most consequential ICA gap, because it can escalate into a fleet correction rather than a single document revision.
- ICAs go stale against their own program: they are frequently drafted before the configuration freezes, so late changes are where coverage breaks.
- An inspection task with no access or criteria instruction is technically present but functionally a gap, because the mechanic cannot execute it.
Sources
U.S. Government (eCFR). Type certificates, STCs (Subpart E), TSO authorizations (Subpart O), PMA (Subpart K), and export airworthiness approvals (Subpart L).
Federal Aviation Administration. STC application process, certification basis, and continued airworthiness obligations of an STC holder.
European Union / EASA. EASA design and production certification, STCs, ETSO authorizations, and EASA Form 1 release.
Frequently asked questions
What if a gap needs analysis that was never done?
We identify the gap and name the analysis it requires, then flag it on the evidence request list so the applicant can commission the work. We reconcile and map existing data; we do not manufacture substantiation that does not yet exist.
Relevant glossary terms
Related pages
Where this fits
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